Field of the Invention
The present invention relates to a counter ejector that is disposed at the most downstream part of a box former and that counts corrugated board boxes and ejects the corrugated board boxes in batches, and a box former using the counter ejector thereof.
Description of Related Art
A box former that manufactures corrugated board boxes includes a counter ejector that counts manufactured corrugated board boxes at the most downstream part of the box former and ejects the corrugated board boxes piled in batches each containing a predetermined number of boxes.
Recently, the speed of manufacturing in the box former has been increased, which has arisen a demand for increasing the processing speed of the counter ejector. In view of the above, there have been proposed various techniques related to the counter ejector.
For example, Patent Literature 1 discloses a counter ejector having the configuration illustrated in FIGS. 10(a)-10(c). As illustrated in FIG. 10(a), the exit (the most downstream section) of a folder gluer 101 and a pair of vertically arranged forwarding rolls 102 are attached to upper stream of the counter ejector of Patent Literature 1. A spanker 111 that depresses the edge of a stack 150 is disposed at a lower portion of the forwarding rolls 102, and a front stop 126 that stops a corrugated board box 103 ejected from the folder gluer 101 and that is movable in forward and backward directions is disposed ahead (downstream) of the forwarding rolls 102.
The space between the spanker 111 and the front stop 126 is a hopper section H in which the sheet-shaped corrugated board boxes 103 are piled as the stack 150.
A support ledge 122a is attached to the bottom of the spanker 111 so as to go into and out of the hopper H. Furthermore, a pusher 124 that pushes the stack 150 is disposed under the support ledge 122a so as to go in and out. Another support ledge 122b is disposed at the bottom of the front stop 126 so as to go into and out of the hopper H. The support ledges 122a and 122b face each other and cooperatively receive the stack 150 on a ledge 136 to be detailed below.
An elevator 129 is disposed below the front stop 126, so that the corrugated board boxes 103 which hit the front stop 126 and fall are received and piled as the stack 150 on the elevator 129. The elevator 129 is substantially horizontally arranged slightly ahead (downstream) of the forwarding rolls 102 and is configured to be vertically movable. A blower 132 that blows air AF on the top surface of the corrugated board box 103 is disposed over the elevator 129. The position of the blower 132 is higher than that of the corrugated board box 103 forwarded from the forwarding rolls 102.
The ledge 136 is disposed opposite to and ahead (downstream) of the forwarding rolls 102. The ledge 136 is configured to be vertically movable and to go into and out of the hopper H. As illustrated in FIG. 10(b), the ledge 136 is activated when the corrugated board boxes 103 received on the elevator 129 and piled as the stack 150 reached a predetermined number, so as to receive corrugated board boxes 103a that are to be piled as a next stack 150a. A vertical direction member 136a of the ledge 136 supports a press bar 138, which depresses the stack 150 and is vertically movable by an air cylinder 139.
An ejecting conveyor 140 is disposed at the same level as the top surface of the elevator 129 when being in the lowest position and at a position sufficiently close to the pusher 124 to handle the minimum box size. When the ledge 136 is activated to receive the corrugated board boxes 103a that are to form the next stack 150a, the elevator 129 immediately starts moving down to the same level as the ejecting conveyor 140. At this time, in order to avoid collapse of the stack 150 due to spring back, the press bar 138 is depressed down from the ledge 136 and thereby the stack 150 is brought down, being sandwiched between the press bar 138 and the elevator 129. When the top surface of the stack 150 passes the support ledges 122a and 122b, the support ledges 122a and 122b project inside the hopper H and come into the stand-by state. Concurrently, the next stack 150a is formed on the ledge 136.
An exit conveyer 141 is disposed downstream of the ejecting conveyor 140 and an upper conveyer 144 is disposed over the exit conveyer 141. The position of the upper conveyer 144 can be adjusted both in the machine direction (i.e., the lateral direction of FIGS. 10(a)-10(c)) and the height direction. The upper conveyer 144 moves in conjunction with the front stop 126 by a predetermined distance from the front stop 126 in accordance with the size of a corrugated board box. As illustrated in FIG. 10(c), after the pusher 124 extrudes the stack 150 on the ejecting conveyor 140 in order for the stack 150 to be sandwiched between the ejecting conveyor 140 and the upper conveyer 144, the upper conveyer 144 brings out the stack 150 in a batch, sandwiching the stack 150 from the top and the bottom in cooperation with the ejecting conveyor 140 and the exit conveyer 141.
When the batch starts moving on the ejecting conveyor 140 as indicated by the arrow in FIG. 10(c), the press bar 138 slightly rises to leave the top surface of the batch and the ledge 136 evacuates in conjunction with the press bar 138 to such a position that the ledge 136 does not interfere with the stack 150a, waiting for the next rise. At this time, the stack 150a on the ledge 136 is supported by the support ledges 122a and 122b. During the above process, the batch completely leaves the elevator 129.
After that, when the elevator 129 rises to the same level as that of the support ledges 122a and 122b, the support ledges 122a and 122b withdraw and the stack 150a, which has been on the support ledges 122a and 122b, is received by the elevator 129. During this movement, the press bar 138 is accommodated in the ledge 136 and the ledge 136 and the press bar 138 together rise and move forward to return to the state of FIG. 10(a). This procedural cycle is repeated until a required number of batches are ejected.
According to the above counter ejector, partly since the ejecting conveyor 140 is disposed sufficiently close to the pusher 124, thereby allowing to handle boxes having a possible minimum size and partly since the upper conveyer 144 can adjust its position in synchronization with the front stop 126, the stroke of the pusher 124 can be shortened, so that a required operation time can be reduced. Since the support ledges 122a and 122b, instead of the ledge 136, temporarily support the stack 150 and the ledge 136 can start the evacuation immediately after the press bar 138 finishes the function of depressing the stack 150, a required operation time can be reduced. In addition, since air pressure from the blower 132 depresses the top surface of the stack 150, such reduction in required operation time can largely reduce the cycle time.